> For the complete documentation index, see [llms.txt](https://docs.materialsproject.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.materialsproject.org/downloading-data/using-the-api/advanced-usage.md).

# Advanced Usage

In addition the `search`, an alternative approach to querying data is with the underlying `_search` function. Instead of using input parameters defined in the client, direct API query parameters are used. Documentation on which of these are available for each endpoint can be found [here](https://api.materialsproject.org/docs) or [here](https://api.materialsproject.org/redoc). While this information is provided, **most people can and should stick to using the standard `search` function.**

The code below is an example illustrating the difference in querying for data from the summary endpoint with volume criteria using `search` and `_search`:

```python
from mp_api.client import MPRester

with MPRester("your_api_key_here") as mpr:
    # -- Using 'search'
    docs = mpr.materials.summary.search(volume=(3,10))
    
    # -- Using '_search'
    docs = mpr.materials.summary._search(volume_min=3, volume_max=10)
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.materialsproject.org/downloading-data/using-the-api/advanced-usage.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.